• 한국물환경학회지
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• 제25권6호
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• pp.886-895
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• 2009

The guideline of selection of Integrated Management Practices (IMPs), such as wood, green roof, lawn, and porous pavement, for Low Impact Development (LID) design was proposed by ranking the reduction rate of surface runoff using LIDMOD1.0. Based on the guideline, LID was designed with several scenarios at two apartment complexes located at Songpa-gu, Seoul, Korea, and the effect of LID on surface runoff was evaluated during last 10 years. The effect of runoff reduction of IMP by land use change was highly dependent on the kind of hydrologic soil group. The wood planting is the best IMPs for reduction of surfac runoff for all hydrologic soil groups. Lawn planting is an excellent IMP for hydrologic soil group A, but reduction rate is low where soil doesn't effectively drains precipitation. The green roof shows constant reduction rate of surface runoff because it is not influenced by hydrologic soil group. Compared to the rate of other IMPs, the green roof is less effect the surface runoff reduction for hydrologic soil group A and is more effect for hydrologic soil group C and D followed to planing wood. The porous pavement for the impervious area is IMPs which is last selected for LID design because of the lowest reduction rate for all hydrologic soil group. As a result of LID application at study areas, we could conclude that the first step of the strategy of LID design at apartment complex is precuring pervious land as many area as possible, second step is selecting the kind of plant as more interception and evapotranspiration as possible, last step is replacing impervious land with porous pavement.

• 한국농공학회:학술대회논문집
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• 한국농공학회 1999년도 Proceedings of the 1999 Annual Conference The Korean Society of Agricutural Engineers
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• pp.493-498
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• 1999

To extract hydrologic information more easily , the pre-processor for hydrologic model using Geographic Information System was developed . This model was applied to the Balan-reservoir watershed which is located at the southwest of Suwon. For estimation SCS curve number, landuse map and hydrologic soil group map were collected from digital map and reconnaissance soil map respectively. The estimated curve number from the GIS technique was 73.

• 한국농공학회논문집
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• 제53권5호
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• pp.9-16
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• 2011

Curve Numbers (CN) for the combination of land use and hydrologic soil group were regionalized at Imha Watershed using Long-term Hydrologic Impact Assessment (L-THIA) coupled with SCE-UA. The L-THIA was calibrated during 1991-2000 and validated during 2001-2007 using monthly observed direct runoff data. The Nash-Sutcliffe (NS) coefficients for calibration and validation were 0.91 and 0.93, respectively, and showed high model efficiency. Based on the criteria of model calibration, both calibration and validation represented 'very good' fit with observe data. The spatial distribution of direct surface runoff by L-THIA represented runoff from Thiessen pologen at Subi and Sukbo rain gage station much higher than other area due to the combination of poor hydrologic condition (hydrologic soil C and D group) and locality heavy rainfall. As a results of hydrologic condition and treatment for land use type based on calibrated CNs, forest is recommended to be hydrologically modelled dived into deciduous, coniferous, and mixed forest due to the hydrological difference. The CNs for forest and upland showed the poor hydrologic condition. The steep slope of forest and alpine agricultural field make high runoff rate which is the poor hydrologic condition because CN method can not consider field slope. L-THIA linded with SCE-UA could generated a regionalized CNs for land use type with minimized time and effort, and maximized model's accuracy.

• 한국물환경학회지
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• 제35권1호
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• pp.72-77
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• 2019

Soil type in LID infiltration practices plays a major role in runoff reduction efficacy. In this study, the effects of infiltration rate of foundation ground under bioretention on annual runoff reduction rate was evaluated using LIDMOD3 which is a simple excel based model for evaluating LID practices. A bioretention area of about 3.2 % was required to capture surface runoff from an impervious area for a 25.4 mm rainfall event. The relative error of runoff from bioretention using LIDMOD3 is 10 % less than that of SWMM5.1 for a total rainfall event of 257.1 mm during the period of Aug. 1 ~ 18, 2017, hence, the applicability of LIDMOD3 was confirmed. Annual runoff reduction rates for the period 2008 ~ 2017 were evaluated for various infiltration rates of foundation ground under the bioretention which ranged from 0.001 to 0.600 m/day and were converted to annual runoff reduction for hydrologic soil group. The runoff reduction rates within hydrologic soil group C and D were steeply increased through increased infiltration rate but not steep within hydrologic A and B with reduction rates ranging from 53 ~ 68 %. The estimated time required to completely empty a bioretention which has a storage depth of 0.632 m is 3.5 ~ 6.9 days and we could assume that the annual average of antecedent rainfall is longer than 3.5 ~ 6.9 days. Therefore, we recommended B type as the minimum hydrologic soil group installed LID infiltration practices for high runoff reduction rate.

• 한국농공학회지
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• 제45권3호
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• pp.94-102
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• 2003

A hydrologic and water quality monitoring network were established in the Balkan-reservoir watershed, which has 29.79 $km^2$ in size, to analyze the characteristics of pollutant loading from an agricultural small watershed. Soil type, land use, hydrologic soil group, population and livestock were also surveyed to make clear the pollutant sources and to calculate the pollutant loadings by the unit loading factor method which was proposed by the Ministry of Environment. From the 5-year hydrologic monitoring results, sub-watersheds located in the upstream of the reservoirs showed higher average runoff ratio. The calculated daily pollutant loadings by the unit loading factor method from HP#2 sub-watershed in the downstream of Balkan reservoir, were much greater than observed.

• 농촌계획
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• 제2권2호
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• pp.91-102
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• 1996

Monitoring techniques for afro-ecological environments were studied, Hydrologic and ecological components in conjunction with water quality were monitored in the Balkan watershed. The hydrologic monitoring program consists of four water level gauging stations along creeks and stream at the watershed having 26.5 km2. Stage - storage relationship of reservoir, rainfall amount of the watershed, and rating curve of the stream gauging stations were established. Soil type, land use, hydrologic soil group, population and economic activities within the watershed were surveyed. Water quality data from the streams were sampled weekly and chemical analysis was conducted. Temporal variations of water quality were investigated and water quality map of each reach of stream was made to identify spatial variations. Seasonal and spatial variations of vegetation densities along stream in the watershed were investigated using grid, Density variations of insect species such as arthropod, flying insect, spider spices, rice insects were also monitored to determine seansonal surveying density. These monitored data will be used to develop monitoring techi%ues and afro - ecological environment models.

• 한국농공학회논문집
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• 제59권5호
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• pp.25-30
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• 2017

Hydrologic soil group is one of the important factors to determine runoff potential and curve number. This study was conducted to classify the hydrologic soil groups of Korean soils by considering saturated hydraulic conductivity and depth of impermeable layer. Saturated hydraulic conductivity of Korean soils was estimated by pedotransfer functions developed in the previous studies. Most of paddy soils were classified as D type due to shallow impermeable layer and low saturated hydraulic conductivity in B soil horizon. For upland and forest, soils classified to A and D types increased compared with former classification method because underestimated permeabilities and overestimated drainages were corrected and rock horizon in shallow depth was regarded as impermeable layer. Soils in mountainous land showed the highest distribution in A type, followed by D type. More than 60 % of soils in mountain foot-slope, fan and valley, alluvial plains, and fluvio-marine deposits were classified to D type because of land use such as paddy and upland.

• 한국지리정보학회지
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• 제7권2호
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• pp.1-15
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• 2004

유역의 유출량을 계산하는 유출모의를 위해서는 직접유출에 기여하는 강우량인 유효강우량을 산정해야한다. 본 연구에서는 SCS CN방법을 이용하여 유효강우량을 산청하기 위해 필요한 유역의 지형자료와 토지피복도 및 토양도 중 정밀토양도의 이용에 관한 내용을 기술하고 있다. 우리나라의 정밀토양도를 SCS CN방법에 적용하기 위해서는 SCS 수문학적 토양군으로의 재분류가 필요하다. 본 연구에서는 정밀토양도를 SCS의 수문학적 토양군으로 분류할 때 허기술과 정정화(1987)의 분류기준과 정정화 등(1995)의 분류기준을 적용하여 유출모의를 수행하여 그 결과를 비교 검토하였다. 대상유역은 IHP 시범유역인 위천 유역과 평창강 유역을 선정하였다. 유출모의는 HEC-1을 이용하였으며 지형인자의 계산은 WMS v6.1을 사용하였다. 대상유역에 대하여 유출모의를 수행한 결과 정밀토양도의 분류방법에 따른 유출모의 결과의 차이는 유역에 따라서 달리 나타날 수 있으나, 정정화 등(1995)이 제시한 기준에 의해서 분류된 정밀토양도를 이용할 경우 대상유역으로 선정한 두 지역에서 모두 실측치에 좀더 근접한 결과를 도출할 수 있는 것으로 나타났다.

• 한국물환경학회지
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• 제25권2호
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• pp.245-255
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• 2009

CN values are changed by various surface condition, which is cover type or treatment, hydrologic condition, or percent impervious area, even the same combination of land use and hydrologic soil group. In this study, CN parameters were regionalized for Nakdong River Basin by Long-Term Hydrologic Impact Assessment (L-THIA) coupled with SCE-UA, which is one of the global optimization technique. Six watersheds were selected for calibration (optimization) and periodic validation and two watersheds for spatical validation as ungauged watershed within Nakdong River Basin. Nash-Sutcliffe (NS) values were 0.66~0.86 for calibration, 0.68~0.91 for validation, and 0.60 and 0.85 for ungauged watersheds, respectively. Urban area for the selected watersheds covered high impervious area with 85% for residential area and 92% for commercial/industrial/transportation area. Hydrologic characteristics for crop area was similar to row crop with contoured treatment and poor hydrologic condition. For the forested area, hydrologic characteristics could be clearly distinguished from the leaf types of plant. Deciduous, coniferous, and mixed forest showed low, moderate, and high runoff rates by representing wood with fair and poor hydrologic condition, and wood-grass combination with fair hydrologic condition, respectively. CN parameters from this study could be strongly recommended to be used to simulate runoff for ungauged watershed.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.50-52
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• 2003

The purpose of this study is to evaluate the hydrological impact due to temporal land cover changes by gradual urbanization of a watershed. WMS HEC-1 was adopted, and DEM with 200m resolution and hydrologic soil group from 1:50,000 soil map were prepared. Land covers of 1986, 1990, 1994 and 1999 Landsat TM images were classified by maximum likelihood method. By applying the model, watershed average CN value was affected in the order of paddy, forest and urban/residential, respectively.